The investigation report into a 2018 Air India Express plane crash at Trichy is a cover-up to exonerate the pilots, says aviation safety expert Captain Mohan Ranganathan. Not only did pilot error result in insufficient thrust, but the cockpit crew allegedly also endangered the lives of the passengers by continuing to fly for close to four hours despite a damaged aircraft in order to ensure that crucial data recording was deleted.
On October 11, 2018, Air India Express's flight from Trichy to Dubai with 130 passengers onboard hit the airport boundary wall and antennas of a ground based navigation aid during take off resulting in a gaping wound in the aircraft belly. Despite the ATC informing the pilots of the damage, the crew continued to fly the Boeing 737-800 till Muscat airspace, where they were ordered to make a landing in Mumbai.
The Aircraft Accident Investigation Bureau in its report made public recently has blamed a snag in the pilot-in-command (PIC)'s reclining seat for the incident. "During the take-off roll, the PIC seat recline mechanism failed causing the seat back to recline at a speed of 117 knots. The PIC was unsettled and handed over the controls to co-pilot. The throttle levers and control column moved back inadvertently as the seat reclined. Neither crew member noticed the reduction of thrust," reads the report.
As the thrust lever slipped back, the take-off thrust was reduced from 98% to 77%, which resulted in the collision. Captain Ranganathan, a former member of Civil Aviation Safety Advisory Council and former airline instructor pilot on Boeing 737NGs, says the probe has been whitewashed to ensure pilots go scot-free.
"The thrust lever moving back to 75% thrust is an indication that it wasn't the backrest that reclined inadvertently, but in fact the pilot failed to lock his seat and the entire seat moved backwards. Only the seat moving back will move your hand back, and along with it the thrust lever," says Captain Ranganathan.
With 75% thrust for almost 25 seconds, it is impossible for the aircraft to accelerate from 115 knots to 143 knots. But the DFDR (Digital Flight Data Recorder) graph has been fudged to show this, he adds. He also asks why the report has not questioned the pilots for deciding to continue to fly the damaged aircraft for four hours.
"The report fails to fault the pilots for continuing to fly. It is evident that the only reason the pilots did not return to Trichy airport and continued to fly the damaged plane for four hours was to ensure that the cockpit voice recorder data during the take off phase was wiped out. This is a criminal act," Captain Ranganathan alleges.